Film cut-out



Nov. 3, 1936. G. J. MEYERS. JR

FILM CUT-OUT Filed. May 1, 1956 JQ ..m n @auf w. team mf el A New# lmoWNH Q ew Gb Patented Nov. 3, 1936 UNITED STATES PATENT OFFICE FILM CUT-OUT New York Application May 1, 1936, Serial No. 77,356

Claims.

The present invention relates to nlm cut-outs and more particularly to oxide lm cutouts which are used in series circuits, especially lighting circuits, to establish a shunt circuit around burnt- '-'5'5 out lamps.

This type of cutout is subject to rough handling and also to all sorts of weather conditions which tend to change the resistance and breakdown characteristics of the insulating film.

One of the diiculties with copper oxide cutouts is that if moisture creeps into the enclosure of the cutout even though it is not suflicient at any one time to cause an immediate breakdown of the oxide lm, it lowers the breakdown strength of the lm. After each drying out the lilm is left in a weaker condition. The eiect of repeated moistening and drying actions is cumulative and the life of the cutout is considerably shortened.

It is an object of my invention to provide an improved moisture-proof casing for an oxide lm cutout.

For a better understanding of my invention, together with other and further objects thereof, reference is had to the following description,

taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the accompanying drawing, Fig. 1 illustrates a cutout made in accordance with my invention mounted for use between the contacts of a series lamp socket; Fig. 2 is a sectional view thereof, and Fig. 3 is an exploded view also in section of the same cutout.

Referring to the drawing in detail, Fig. 3 illustrates the elements of the cutout including a metal disk 5, preferably circular, provided with a peripheral ilange 6 arranged at right angles to the disk and a raised portion 'I at its center. A gasket 8 of an insulating material, such as water- 40 proofed fabric for example, comprises a circular ring 9 and a peripheral ange I0 at right angles thereto. The outside diameter of the flange I0 is somewhat smaller than the inside diameter of the flange 6, so that this gasket 8 ts into the cup-shaped member consisting of the disk 5 and its flange 6. The cutout element II comprises an oxide coated metal disk II having a smaller diameter than the disk 5 and being provided with 5 a raised portion I2. This cutout element is designed to lie contiguous to the disk 5 and its raised portion to fit over the raised portion 'I on the disk 5. A cover I3, comprising a metal disk I4, provided with a concentric raised portion I5 and an offset peripheral flange I6, is used as a (Cl. 20D- 118) cover for the casing comprising the disk 5 and the flange 6. The flange I6 on the disk cover I4 is offset merely enough to provide room for the cutout element II when the disks are assembled. The width of the flange I6 is made sub- *5 stantially equal to the width of the gasket ring 9, so that when the elements of the cutout are assembled broad moisture-tight joint is made extending inward from the periphery for a substantial distance which is several times the thick- 10 ness of the insulation.

In assembling the cutout the gasket is placed inside of the flange 6 so that the ring 9 is contiguous to the disk 5 and the flange I0 is contiguous to the flange 6. The cutout element is 15 placed contiguous to the disk 5 and the cover I3 is placed inside of the flange 6 and contiguous to the other side of the cutout element I I. When these elements are thus assembled, the flange 6 is rolled over as illustrated in Fig. 2. When this is done the insulating material of the gasket in- 0 cluding ring 9 and the iiange I0 overlies the periphery and both surfaces of the flange I6 on the edge of the disk I3 and thereby insulates this disk from the disk 5. It will be noted that the path for any moisture to creep into the enclosure and reach the cutout II is along the entire surface of the gasket 8 including the ange I0 and the ring 9 and the adjacent surfaces of the flanges 6 and I6. This path is given a length many times greater than the thickness of the insulating material and by applying a. reasonable pressure during the rolling process the material of the gasket adheres to the surfaces of the disks and the flanges so that the casing thus formed becomes moisture-proof. Furthermore, only the outer edge of this insulation is exposed to the atmosphere and the remainder of this insulation is protected by the metal of the casing against physical damage and deterioration due to atmospheric actions. It is, therefore, able to withstand the entrance of moisture into the casing for a long period of time. Simultaneously a full thickness of the insulation of the disk 9 and ange I0 is retained at all points between the two members of the cutout casing and the necessary electrical insulation between the parts of the casing is maintained. This insulation is, of course, higher than the breakdown strength of the lm within the casing and which is protected thereby. In Fig. 1 I have illustrated the cutout placed between the prongs I9 and 20 of a series socket, the prong 20 being in contact with the disk 5 and the prong I9 being in contact with the raised portion I5 on the cover element I3. 55

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a film cutout, the combination of an insulating lm covered member, a casing therefor comprising a pair of metal disks contiguous to the two sides of said lm, and an insulating member for separating said disks along their edges, the width of said insulating member being greater than its thickness whereby the creepage of moisture into the casing is prevented and a minimum of insulation is exposed to atmosphere.

2. In an oxide lm cutout, the combination of a casing comprising a disk provided with a flange, a second disk comprising a cover therefor, an oxide film covered element between adjacent surfaces of said disks and an insulating gasket between said disks and said ange, said gasket comprising a ring between the said disks and a flange arranged between the edge of one disk and the flange on the other disk, said ilange being rolled over the edge of said second disk and said insulating gasket extending beyond the edge of said rolled-over flange.

3. A film cutout comprising a pair of metal disks, an insulating lm having a predetermined breakdown strength between said disks, an insulating gasket overlying the edge of One of said disks, and a ange on the other of said disks overlying said insulating gasket and holding said elements in assembled relation.

4. A film cutout comprising a pair of metal disks, an insulating film covered member having a smaller diameter than said disks arranged contiguous to adjacent sides of said disks, an insulating gasket arranged to cover the peripheral edge of one of said disks and both sides of said disk for a substantial distance from said edge, and a flange integral with the other disk arranged to substantially cover said insulation on the outer side of said one disk,

5. A lm cutout comprising a pair of metal disks, an insulating film having a predetermined breakdown strength arranged contiguous to adjacent sides of said disks, an insulating member overlying the edge of one of said disks, and means engaging the exposed portion of said insulating member and the edge of the other of said disks for holding said members in assembled relation.

GEORGE J. MEYERS, JR. 

